A. Field of the Invention
The present invention relates to the fields of microbiology and infectious pathology. More particularly, it deals with the identification of peptides that are capable of inhibiting bacterial infections, including those caused by Haemophilus influenzae and Staphylococcus aureus. 
B. Related Art
Nasopharyngeal colonization with non-encapsulated Haemophilus influenzae (NTHi) frequently occurs in infants and in adults with common variable immunodeficiency (CVID), but is rarely found among healthy adults. In children with recurrent episodes of acute otitis media (RAOM), NTHi is more common than in healthy individuals. Protracted nasopharyngeal colonization with one and the same NTHi strain has also been found in CVID patients. Colonization is suspected to cause deeper infections, e.g., sinusitis and pneumonia. Since they early 1990's, however, there has been an increase in invasive NTHi infections in previously healthy people.
Similarly, Staphylococcus aureus clinical isolates with intermediate resistance to glycopeptides, so called GISA isolates, have recently been recognized in Japan, the U.S. and elsewhere (Ploy et al., 1998; Wong et al., 1999). GISA isolates described to date have been uniformly resistant to methicillin and have sorted into three phenotypic classes (Boyle-Vavra et al., 2000). All are heteroresistant in that only a subpopulation of cells express the vancomycin resistance phenotype. Class A isolates are intermediate to vancomycin and teicoplanin; class B isolates are intermediate to vancomycin but susceptible to teicoplanin. Class C isolates have an MIC of teicoplanin in the intermediate range and vancomycin in the susceptible range (Boyle-Vavra et al., 2000). Additionally, isolates have been described that are susceptible to both glycopeptides by minimum inhibitory concentration (MIC) testing, but contain a subpopulation that can survive on vancomycin >4 μg/ml. The mechanism of glycopeptide resistance in S. aureus remains unclear.
Thus, there is a growing need to identify new and improved antibiotics that are effective at preventing and treating these difficult to treat and quite dangerous bacterial infections.